There is an air conditioning system that generates warm water or cold water by a heat source device such as a heat pump device, and sends the generated warm water or cold water to an indoor heat exchanger in order to perform heating or cooling in a room.
Generally, this air conditioning system is a method of evening out a temperature of water without depending on an air conditioning load, and for example, warm water of 35° C. is supplied to the indoor heat exchanger in the heating time, and cold water of 16° C. is supplied to the indoor heat exchanger in the cooling time. According to this method, in the case of the air conditioning load being small, such as in a period between seasons, a control is carried out such that the heat source device is stopped when the indoor temperature becomes a set value, or such that water supply to the indoor heat exchanger is stopped by controlling a three-way valve, etc. Therefore, the heating operation or the cooling operation is performed intermittently, and thereby reducing the user's comfort and decreasing the operational efficiency.
Moreover, there is an air conditioning system with a function that an installation contractor in installing the air conditioning system sets up a target temperature of water supplied by the heat source device according to an anticipated outdoor temperature. This air conditioning system is effective when a set target temperature is suitable for the air conditioning load. However, due to seasonal change etc., there may a case in which a target temperature is low for the air conditioning load, or a target water temperature is high for the air conditioning load. In such a case, operation of deficient performance or of excessive performance will be performed, thereby reducing the user's comfort and decreasing the operational efficiency.
Moreover, in Patent Literature 1, there is described a control method of re-setting a target temperature of water supplied by the heat source device, based on deviation between a target indoor temperature which a user set and a current indoor temperature. In Patent Literature 1, it is intended, by this control method, to realize high operational efficiency without reducing the comfort.